Global Patent Index - EP 0166412 A3

EP 0166412 A3 19860319 - POLYCRYSTALLINE SINTERED BODIES BASED ON SILICON NITRIDE AND SINTERING ADDITIONS

Title (en)

POLYCRYSTALLINE SINTERED BODIES BASED ON SILICON NITRIDE AND SINTERING ADDITIONS

Publication

EP 0166412 A3 19860319 (DE)

Application

EP 85107801 A 19850625

Priority

DE 3423573 A 19840627

Abstract (en)

[origin: US4814301A] The invention relates to polycrystalline sintered articles comprising at least 50% by weight of crystalline silicon nitride phase of which at least 90% by weight is in the beta -form, and at least one secondary crystalline intergranular silicate phase, and having a density of at least 99% of the theoretically possible density, a modulus of elasticity at room temperature of less than 300 kN/mm2, a short-term bending strength at room temperatue, measured according to the 4-point method, of at least 600 N/mm2 which, up to 1200 DEG C., decreases by less than 50%, and a long-term bending strength, measured according to the 4-point method, which is characterized by a numerical value of more than 40 at 1200 DEG C. for the crack growth resistance parameter n. These polycrystalline sintered articles are manufactured, by sintering with or without the use of pressure, a mixture of silicon nitride powder, crystalline silicates of natural or synthetic origin having melting points in the range of from 1350 DEG C. to 1950 DEG C. as sintering additives and metal carbides having melting points at least from 1500 DEG C. as nucleus formers.

IPC 1-7

C04B 35/58

IPC 8 full level

C04B 35/58 (2006.01); C04B 35/584 (2006.01); C04B 35/593 (2006.01)

CPC (source: EP US)

C04B 35/584 (2013.01 - EP US); C04B 35/593 (2013.01 - EP US); C04B 35/5935 (2013.01 - EP US)

Citation (search report)

  • [XP] WO 8500593 A1 19850214 - FORD MOTOR CANADA [CA], et al
  • [X] US 4264550 A 19810428 - EZIS ANDRE
  • [A] DE 2351163 A1 19750430 - ANNAWERK KERAMISCHE BETR E GMB
  • [X] CHEMICAL ABSTRACTS, Band 90, Nr. 14, 2. April 1979, Seite 295, Nr. 108536b, Columbus, Ohio, US; J.E. WESTON et al.: "Crystallization of grain boundary phases in hot-pressed silicon nitride materials. Part 1. Preparation and characterization of materials" & J. MATER. SCI. 1978, 13(10), 2137-46
  • [A] CERAMIC ENGINEERING AND SCIENCE PROCEEDINGS, Band 5, Nr. 5/6, Mai-Juni 1984, Seiten 385-396, Columbus, Ohio, US; A.E. PASTO: "Silicon nitride-cordierite composites for Diesel engine applications"
  • [A] CHEMICAL ABSTRACTS, Band 86, Nr. 8, Februar 1977, Seite 191, Nr. 46587a, Columbus, Ohio, US; TAI-II MAH: "Densification studies of silicon nitride" & DISS. ABSTR. INT. B 1976, 37(5), 2400

Designated contracting state (EPC)

AT BE CH DE FR GB IT LI NL SE

DOCDB simple family (publication)

EP 0166412 A2 19860102; EP 0166412 A3 19860319; EP 0166412 B1 19880921; AT E37352 T1 19881015; DE 3423573 A1 19860109; DE 3565096 D1 19881027; JP S6114173 A 19860122; US 4814301 A 19890321

DOCDB simple family (application)

EP 85107801 A 19850625; AT 85107801 T 19850625; DE 3423573 A 19840627; DE 3565096 T 19850625; JP 6857785 A 19850402; US 13558087 A 19871221